Semiconductor memory is widely used in various electronic devices such as cellular telephones, digital cameras, personal digital assistants, medical electronics, mobile computing devices, and non-mobile computing devices. Semiconductor memory may comprise non-volatile memory or volatile memory. A non-volatile memory allows information to be stored and retained even when the non-volatile memory is not connected to a source of power (e.g., a battery). Examples of non-volatile memory include flash memory (e.g., NAND-type and NOR-type flash memory) and Electrically Erasable Programmable Read-Only Memory (EEPROM).
A data storage device that includes semiconductor memory may be in communication with a host system through an interface. In some cases, more than one data storage device may be in communication with a host system through one or more interfaces. Various standardized interfaces may be used for communication between components including data storage devices and a host system, including Peripheral Component Interface (PCI), PCI express (PCIe), Serial ATA (SATA), Serial Attached SCSI (SAS), Non-Volatile Memory Host Controller Interface Specification (NVMHCIS) or NVM Express (NVMe), and other interfaces.
A data storage device may include one or more control circuits that facilitate operation of semiconductor memory, e.g. a memory controller coupled to a non-volatile memory. Some circuits include an interface for debugging, e.g. specific pins for accessing debugging. An example is an interface specified by the Joint Test Action Group (JTAG) standard. Such an interface provides access to debugging data in an integrated circuit (IC) such as a memory controller.